Variable capacity gear pump



March 7, 1939. e. w. WILKIN VARIABLE CAPACITY GEAR PUMP 4 Sheet-Sheet 1 Filed April 27, 1957 a 4 7 5 M m Wi d 0. a w w W? w m 0. o m l w I. o o A0 0 w L m. a 0 Q 7 V Fm 0 a w H i I i M V 7 J I I 6 2 w a W O 0 80 w INVENTOR. Qemqw 91 /1 QW/I/(iK/ZW I a ATTORNEY March 7, 1939. s. w. WILKIN 2,149,326

VARIABLE CAPACITY 'GEAR PUMP Filed April 27, 1937 4 Sheets-Sheet 2 i I INVENTOR.

Savage/Q10 WWW,

a Cl 1 M ATTORNEY March 7, 1939. I G. w. WILKIN I 2,149,326

VARIABLE CAPACITY GEAR PUMP W y 3?;15 I W16, v fif T- I 6 I a M 'M /5 H l. 'I

ee 9w $29.

ATTORNEY v March 1939- G. 'w.- WILKIN 2,149,326

I VARIABLE CAPACITY GEAR PUMP' 7 Filed April 27, 1937 4 Sheets-Sheet 4.

. ILE- Y IN V EN TOR.

Sway W Wm,

a. m, ATTORNEY,

Patented Mar. 7 1 939 UNITED STATES PATENT OFFICE 7 Claims.

This invention relates to certain new and useful improvements in gear pumps.

' The main object of the invention is to provide a gear pump which may be used for transmitting power or for pumping various kinds of liquids or semi-liquids, which develops high forcing power and may be operated efiiciently at high speed and throughout a wide range of speeds, andwhich embodies novel means for preventing leakage losses or clogging of the teeth of the gears and .for varying the effective capacity of the pump at will.

A further object of the invention is to provide a gear pump which is simple of construction,

adapted to be manufactured and sold at a comparatively low cost, and which is of highly durable type and not liable to easily get out of order.

The invention consists of the features of construction, combination and arrangement of parts, hereinafter fully described and claimed, reference being had to the accompanying drawings, in which:

Fig. 1 is a horizontal central section through a gear pump embodying my invention.

Fig. 2 is an end elevation of the pump with parts broken away and in section.

Figs. 3, 4 and 5 are transverse sections on th lines 33, 4--4 and 55 of Fig. 1.

Fig. 6 is a view showing a modification in the form of the gears.

Fig. '7 is a side elevation of the pump.

Fig. 8 is a top plan view thereof.

The pump comprises a casing or housing I having a rear main portion 2 and a relatively reduced forward portion 3, each of substantially elliptical form in cross-section. This casing is normally open at each end to admit of the application and v removal of its working parts and the rear end of the portion 2 is closed in service by a detachable cover plate 4, while the forward end of the portion 3 is closed in service by an inner bearing plate5 and an outer cover plate 6, detachably secured in position.

A main rotary drive shaft 1 extends longitudinally and axially within the casing and has its rear end 8 projecting beyond the cover plate for suitable driving connection with a prime mover,

which may be a gasoline or other type of engine.

maintain sufficient seal for a good pumping effect.

tion a stop shoulder l4.

Keyed to the shaft 1 for rotation thereby and 5 therewith is a central drive and pump gear 15, and meshing with this gear I5 and rotatable aboutthe shafts II are pump gears I6, It, all of which gears are mounted in the casing portion 2. The teeth I! of these gears are bulbous-shaped and flattened at their peripheries to bear against curved walls ll of the casing against which they bear, except at the points of engagement of the teeth of the gears with one another, in order to The teeth of the center gear l5 are provided with drain passages i8 for drainage of oil from the spaces between them in certain positions of said gear. The rounded surfaces of the bulbous gear teeth provide for a close meshing engage- 20 ment of the teeth for a substantially fluid tight action to secure an eificient pumping effect. At the top and bottom of the casing are sets of intake and outlet ports I9, I9, and 20, 20', for connection with feed and. return pipes 2|, 2| and 22 and 22' leading from a source of fluid supply and to a fluid delivery point, or to a motor or motors to be driven, such as a motor of the type shown in my copending application, Serial No, 148,991, flied June 18, 1937, to supply and pressure controlling tanks of a power system.

Each gear l6, I6 is rotatable on an inner sleeve 23 which at its forward portion is mounted in an Outer sleeve 24 carrying'at its inner end a head or follower plate 25. The gear l6 or I6 is held between this follower plate and a flange or head 7 26 at the rear end of the sleeve 23 against independent sliding movement and so as to be slidable with the sleeves in their sliding movements. Each sleeve 23 has a reduced forward end 21 which passes through a yoke head or plate 28 and is fastened thereto for sliding movements therewith by securing and check nuts 29. The forward end of each sleeve 24 abuts against the inner face of this yoke plate and is held between the same and theforward end of the associated gear IE or IE so as to be slidable with the inner sleeve and yoke plate, by which means the two gears l6 and I6 may be slidably adjusted longitudinally of the casing and with relation to the rotatable but non-slidable driving gear IE to regulate the extent of engagement of the teeth of said gears and the effective pumping action of by rods 30, which extend outwardly through the bearing and cover plates 5 and t, with a yoke bar 3| arranged on the outside of and at the rear end of the pump casing, to which bar motion may be imparted as by means of a lever or other operating device 3! to slide the rods Bliinwardly or outwardly and to correspondingly slide the yoke plate 28 and inner and outer sets of sleeves to shift the gears l6 and it rearwardly so as to reduce the effective pumping capacity of the pump or to slide said gears forwardly to progressively increase the pumping capacity of the pump up to a maximum degree, at which the teeth of the gears "5, i6 and it are engaged throughout their tween the teeth of the gears til, it and it? left vacant by rearward adjustment of the gears l6, l6 in order to properly block the spaces between the non-engaging portions of the teeth of the gears and prevent escape of the iiuid from said spaces, whereby the pumping emciency of the gears at any capacity ratio will be maintained. The means employed for this purpose comprises a series of freely rotatable and slidable blocking elements 34, 35 and 35, each consisting of a rotatable member shaped similar to the gears but having inwardly projecting tooth-like blocking projections of a formation corresponding to the formation of the spaces between the teeth of the gears to seal the same against escape of fluid. The blocking member 3t is disposed between the forward end of the gear 55 and the yoke head or plate 28 and is rotatably connected to said yoke head or plate 28, as shown at 3%, and the rear ends or the tooth-like projections tit or said blocking element 34 normally extend a short distance within the spaces between the teeth of the gear l5 and in abutting engagement with adjacent ends of the teeth of the gears it, it, so that when said gears it and it are moved rearwardly the blocking projections of the blocking member 34 will follow the same in their movements and close the forward portions of the spaces between the teeth of the gear 55 which would otherwise be left vacant. The blocking members 35 and 35 are similar in form to the blocking member 3-3 and are rotatable about the stationary shafts H and are provided between the tooth like projections 35a thereof with recesses 31 to receive and permit rearward sliding movements of the inner sleeves thereinto when said sleeves are adjusted rearwardly. The spaces between the forward ends of these tooth-like projections 35a of the blocking members 35 and 35 are normally engaged by the rear ends of the teeth of the gears l6 and itso that the gears and blocking members are normally in guided engagement, whereby when the gears 05 and I5 are slid rearwardly the portions of the spaces at the rear ends thereof passing beyond the teeth of the gear IE will be closed by the projections of the blocking members to prevent leakage of the motive fluid therefrom. It will, of course, be understood that the gears may be driven at any desired speed and it will be seen that the pumping capacity of the pump at any speed may be varied to wide degrees by adjustment bf the gear members 115, it, so that the capacity flow of the fluid may be varied to correspondingly vary the power applied to the motor or motors to be driven thereby. The provision of the blocking devices prevents loss of fluid from between the gears at times when the sliding gears are adjusted rearwardly and at all other times so that a pump of maximum efficiency is produced. By varying the speed of the pump gears and their capacity a high degree of flexibility of the pumping action within minimum and maximum limits may be obtained to regulate the speed and power of the. driven parts as desired, and such speed and power may be increased or reduced as quickly as desired without causing backlash or undesirable fluctuations of the fluid being pumped.

Fig. 6 illustrates a modification in the form of the pump gears, in which the center gear its. mounted on shaft "17a and one of the side gears ltd rotatable about its stationary shaft Ha are r shown. In this modified form the gear teeth llc are substantially semi-elliptical shaped and are provided in their sides with drain recesses its.

This construction of the gears ensures a perfect meshing of the teeth and provides at the inner extremities of their curved sides points of contact and between the outer and inner extremities of their curved sides rounded surfaces foreasy meshing engagement. Such construction also provides for the formation between engaged teeth of a drain channel it communicating with the recesses 98a to allow ready escape of entrapped fluid to prevent liability of fluid jamming and irregularities of action due to this cause.

From the foregoing description, taken in connection with the drawings, the construction and mode of operation of my novel and improved gear pump will be readily understood without a further and extended description, and it will be seen that the invention provides a simple, reliable and efficient construction of pump embodying means whereby the efiective capacity of the pump may be varied within wide limits and whereby suclr action may be obtained by a relative shifting of the pump gears without loss of pumping eficiency, owing tothe fact that by simultaneous adjustment of the fillers or blocking devices the vacant spaces between the gear teeth will be filled to prevent leakage of the power iiuid therebetween. It will also be seen that the sliding gears and blocking means may be simultaneously operated in a ready, convenient and expeditious manner so that the pump may be driven at any speed and its capacity regulated closing the ends of the casing, a central drive shaft journaled in said heads, stationary shafts carried by the heads and disposed on opposite sides of the drive shaft, a central pump gear carried by the drive shaft, sleeves slidably mounted on the stationary shaft, pump gears arranged on opposite sides of the central pump gear and meshing therewith, said side gears being rotatable about and slidable with the sleeves, the easing being provided with a set of fluid intake and discharge ports for cooperation with each of the side gears-and the central gear, a cross yoke extending between and connecting the sliding sleeves, means extending through one of said heads and coupled to the cross yoke for sliding said side gears for varying their extent of meshing engagement with the central gear and the pumping capacity of the pump, and means rotatable with the gears and relatively slidable therewith in their sliding actions for filling the spaces between the teeth of the gears-left vacantby the relative slidingw movement of the gears in disengaging direction.

2. A gear pump comprising a casing, heads closing the ends of the casing, a central drive shaft journaled in the heads, stationary shafts disposed on opposite side of the central shaft and carried by the heads, sleeves slidable onthe'stationary'shafts, a central pump gear mounted on for varying their extent of meshing engagement.

and pumping capacity, rods connected to the yoke on opposite sides of its center and extending outwardly through and slidable in one of said heads, a cross connection between the outer ends of the rods, an operating lever coupled to said cross connection, and means rotatable with the gears and relatively slidable, therewith in the sliding motions of the side gears for filling the spaces between the teeth of the gears left vacant in the relative sliding motions of the gears in disengaging direction.

3. A gear pump having a set of three pumping gears comprising a driven center gear and two side gears intermeshing with the center gear, said center gear being rotatable in a fixed plane, an inner flanged sleeve and an outerfianged sleeve for supporting and sliding each side gear with relation to the center gear to vary the extent of meshing engagement of said gears and their pumping capacity, said sleeves being concentrically mounted and each side gear being rotatably mounted on its inner supporting sleeve and held between the flanges of the sleeves for sliding movement with the sleeves, a pair of toothed fillers rotatable in fixed planes with the gears and adapted to fill the spaces between the teeth of the side gears left vacant by a disengagi movement of the side gears relative to the center gear, a toothed fillerrotatable with the gears and sl'dable with the side gears and adapted to fill the spaces between the teeth of the center gear eft vacant by such disenga ing movement of the side gears, and means connected with the sleeves of the side gears for simultaneously sliding said side gears and slidable filler.

4. Agearpumphaving asetofthreepumping gears comprising a driven center gear and two side gears intermeshing' with the center sear. said center gear being rotatable in a fixed plane, and said side gears being slidable with relation to the center gear to varythe extent of meshing engagement of said gears and their pumping capacity, a pair of toothed fillers rotatable in fixed planes with thegears and adapted to fill the spaces between the teeth of the side gears left vacant by a disengaging movement of the side gears relative to the center gear, a toothed filler rotatable with the gears and slidable with the side gears and adapted to fill the spaces between the teeth of the center gear left vacant by such disengaging movement of the side gears, a slidable cross yoke connection between the sleeves of said side gears and slidable filler, and operating means coupled to said yoke connection.

5. A rotary gear pump comprising a casing. heads closing the ends of the casing, a drive shaft journaled in the heads, stationary shafts carried by'the heads and arranged on'opposite sides of the drive shaft, a toothed central pump gear carried by and rotatable with the drive shaft, toothed gears arranged on opposite sides of the center gear and meshing therewith, said side gears being driven by the center gear and slidable with relation thereto to vary the extent of engagement of the teeth of the gears, sets of sliding sleeves slidably mounted on the stationary shafts for slidably shifting the side gears, each set of sleeves comprising an inner sleeve on which a side of the gear is rotatably mounted and an outer concentric sleeve, said sleeves having flanges holding the side gear confined for sliding movement with said sleeves, a cross yoke connecting the sets of sleeves for sliding movements together, rotatable toothed fillers for closing the spaces between the portions of the teeth of the side gears left vacant by movement'of the side gears in disengaging direction, a slidable and rotatable toothed filler rotatably mounted on and slidable with said yoke forclosing the spaces between theportions of the teeth .of the center gear left vacant by such disengaging movement of the side gears, and means connected with the yoke for sliding the side gears and the slidable filler in unison.

6, A rotary gear pump comprising a casing, a drive shaft journaled in the casing, stationary shafts mounted in the casing on opposite sides of the drive shaft, a central pump gear mounted on the drive shaft,- side pump gears rotatable about the stationary shafts, sleeves ca ng said side gears and mounting the same fo sliding movements relative to the center gear for varying the extent of meshing engagement of the teeth of the gears and the capacity of the pump, toothed fillers rotatable with the. side gears and adapted to receive the same in their sliding movementsand to fill the vacant spaces between the teeth thereof by disengagement of said teeth with the teeth of the center gear, connecting means between the sleeves for sliding them in unison, and a filler rotatable on said connecting means and with'the center gear and slidable with the side gears for closing the spaces between the teeth of the center gear opposite the first-named fillers.

7. A gear pump comprising a casing, a drive shaft journaled in the casing, a center gear carried by said shaft, stationary shafts mounted in the casing on" opposite sides of the drive shaft,

side gears meshing with the center gear and slidneously sliding said sleeves.

' GEORGE W. Wm. 

